import java.util.Scanner;

public class mm {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String s = in.nextLine();
        for(int i=0;i<=9;i++){
            s=s.replace(Integer.toString(i),"");
        }
        char[] ch = s.toCharArray();


        for(int i = ch.length-1; i >= 0 ; i--) {
            System.out.print(ch[i]);
        }

    }
}